Exposed portion of a printed circuit board (PCB) configured to provide isolation among radar antennas

ABSTRACT

This document describes techniques and systems of an exposed portion of a PCB configured to provide isolation among radar antennas. The described radar system includes an exposed portion of a surface of a printed circuit board (PCB) positioned between a first antenna and a second antenna. The PCB includes a metal plating on the surface of the PCB. A width of the exposed portion can delay a phase of electromagnetic (EM) energy conducted by the metal plating relative to a phase of EM energy that does not traverse the exposed portion. A height of the exposed portion can cause an amount of the EM energy conducted by the metal plating to be approximately equal to an amount of EM energy that traverses the exposed portion. In this way, the described systems and techniques can reduce signal-coupling among radar antennas without additional hardware costs and distance between the antennas.

BACKGROUND

Radar systems use electromagnetic signals to detect and track objects.The electromagnetic signals are transmitted and received using one ormore antennas. In automotive applications, the antennas may bepositioned tightly near one another for compactness or to achieve aparticular radar effect. Signal-coupling can occur between two or morenearby antennas; a portion of the electromagnetic signals transmitted orreceived from one antenna couple with the electromagnetic signalsreceived or transmitted by another antenna. Signal-coupling can induce arelatively large noise-floor in the radar system. It is desirable toreduce signal-coupling without introducing additional hardware,complexity, and/or cost, in particular, while maintaining a compactdesign.

SUMMARY

This document describes techniques and systems of an exposed portion ofa printed circuit board (PCB) configured to provide isolation amongradar antennas. For example, a radar system includes a printed circuitboard (PCB) that includes a first antenna and a second antenna on asurface of the PCB. The first antenna and the second antenna areconfigured to emit or receive electromagnetic (EM) energy. The PCB alsoincludes a metal plating on the surface of the PCB. The metal platingcan conduct a portion of the EM energy from the first antenna on thesurface of the PCB, and the second antenna can receive the portion ofthe EM energy conducted by the metal plating. An exposed portion of thePCB surface, which is positioned between the first antenna and thesecond antenna, represents an area of the surface of the PCB without themetal plating. A width of the exposed portion can delay a phase of afirst part of the portion of the EM energy that traverses the exposedportion relative to a phase of a second part of the portion of the EMenergy that does not traverse the exposed portion. A height of theexposed portion can cause an amount of energy of the first part of theportion of the EM energy to be approximately equal to an amount ofenergy of the second part of the portion of the EM energy.

This document also describes methods performed by the above-summarizedsystem and other methods set forth herein, as well as means forperforming these methods.

This Summary introduces simplified concepts related to an exposedportion of a PCB configured to provide isolation among radar antennas,which are further described below in the Detailed Description andDrawings. This Summary is not intended to identify essential features ofthe claimed subject matter, nor is it intended for use in determiningthe scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

The details of one or more aspects of one or more exposed portions of aPCB configured to provide isolation among radar antennas are describedin this document with reference to the following figures. The samenumbers are often used throughout the drawings to reference likefeatures and components:

FIG. 1 illustrates an example environment in which a radar system withone or more exposed portions of a PCB configured to provide isolationamong radar antennas can be implemented;

FIG. 2 illustrates an example antenna with a window for isolation amongantenna arrays;

FIG. 3 illustrates another example antenna with a window for isolationamong antenna arrays;

FIG. 4 illustrates an example antenna with multiple windows forisolation among antenna arrays; and

FIG. 5 illustrates an example method of an exposed portion of a PCBconfigured to provide isolation among radar antennas.

DETAILED DESCRIPTION

Overview

Radar systems are an important sensing technology that some automotivesystems rely on to acquire information about the surroundingenvironment. Some radar systems include at least two antennas totransmit and receive EM radiation. For example, radar systems include atleast one transmit antenna to emit EM radiation and at least one receiveantenna to receive EM radiation that reflects off nearby objects.Signal-coupling among multiple radar antennas can introduce a relativelylarge noise floor into the radar system.

Some radar systems include a barrier wall or absorber between antennasto reduce signal-coupling between them. In addition to increasing thehardware cost of the radar system, a barrier wall or absorber canpartially block the antennas' field of view.

Other radar systems increase the distance among the antennas. Theincreased distance generally does not significantly reduce thesignal-coupling among the antennas and increases the size of the radarsystem. For many applications, including automotive applications, it isdesirable to minimize the size of radar systems, and in particular, thesize of their antennas.

In contrast, this document describes techniques and systems to isolateantennas in radar systems without additional hardware costs andcomplexities, or further distancing among the antennas. For example, aradar system can include an exposed portion of a surface of a PCBpositioned between a first antenna and a second antenna. The PCBincludes a metal plating on the surface of the PCB. A width of theexposed portion can delay a phase of EM energy conducted by the metalplating relative to a phase of EM energy that does not traverse theexposed portion. The height of the exposed portion can cause an amountof the EM energy conducted by the metal plating to be approximatelyequal to an amount of EM energy that traverses the exposed portion. Inthis way, the described systems and techniques can reducesignal-coupling among radar antennas without a barrier wall orincreasing the size of the radar system.

This is just one example of the described techniques and systems of anexposed portion of a PCB configured to provide isolation among radarantennas. This document describes other examples and implementations.

Operating Environment

FIG. 1 illustrates an example environment 100 in which a radar system102 with one or more an exposed portion of a PCB configured to provideisolation among radar antennas can be implemented. In the depictedenvironment 100, the radar system 102 is mounted to, or integratedwithin, a vehicle 104. The radar system 102 is capable of detecting oneor more objects 108 that are in proximity to the vehicle 104. Althoughillustrated as a car, the vehicle 104 can represent other types ofmotorized vehicles (e.g., a motorcycle, a bus, a tractor, a semi-trailertruck, or construction equipment), non-motorized vehicles (e.g., abicycle), railed vehicles (e.g., a train or a trolley car), watercraft(e.g., a boat or a ship), aircraft (e.g., an airplane or a helicopter),or spacecraft (e.g., satellite). In general, manufacturers can mount theradar system 102 to any moving platform, including moving machinery orrobotic equipment.

In the depicted implementation, the radar system 102 is mounted on thefront of the vehicle 104 and provides a field-of-view 106 illuminatingthe one or more objects 108. The radar system 102 can project thefield-of-view 106 from any exterior surface of the vehicle 104. Forexample, vehicle manufacturers can integrate the radar system 102 into abumper, side mirror, headlights, rear lights, or any other interior orexterior location where the object 108 requires detection. In somecases, the vehicle 104 includes multiple radar systems 102, such as afirst radar system 102 and a second radar system 102 that togetherprovide a larger field-of-view 106. In general, vehicle manufacturerscan design the locations of the one or more radar systems 102 to providea particular field-of-view 106 that encompasses a region of interest inwhich the object 108 may be present. Example fields-of-view 106 includea 360-degree field-of-view, one or more 180-degree fields-of-view, oneor more 90-degree fields-of-view, and so forth, which can overlap or becombined into a field-of-view 106 of a particular size.

The object 108 is composed of one or more materials that reflect radarsignals. Depending on the application, the object 108 can represent atarget of interest. In some cases, the object 108 can be a moving objector a stationary object. The stationary objects can be continuous (e.g.,a concrete barrier, a guard rail) or discontinuous (e.g., a trafficcone) along a portion of the road.

The radar system 102 emits electromagnetic radiation by transmitting oneor more electromagnetic signals or waveforms via active elements. In theenvironment 100, the radar system 102 can detect and track the object108 by transmitting and receiving one or more radar signals. As anexample, the radar system 102 can transmit electromagnetic signalsbetween 100 and 400 gigahertz (GHz), between 4 and 100 GHz, or betweenapproximately 70 and 80 GHz.

The radar system 102 can determine a distance to the object 108 based onthe time it takes for the signals to travel from the radar system 102 tothe object 108, and from the object 108 back to the radar system 102.The radar system 102 can also determine a location of the object 108 interms of an angle based on the direction of a maximum amplitude echosignal received by the radar system 102.

The radar system 102 can be part of the vehicle 104. The vehicle 104 canalso include at least one automotive system that relies on data from theradar system 102, including a driver-assistance system, anautonomous-driving system, or a semi-autonomous-driving system. Theradar system 102 can include an interface to the at least one automotivesystem, wherein the antenna 114 can output, via the interface, a signalbased on EM energy received by the antenna 114.

Generally, the automotive systems use radar data provided by the radarsystem 102 to perform a function. For example, the driver-assistancesystem can provide blind-spot monitoring and generate an alert thatindicates a potential collision with the object 108 that is detected bythe radar system 102. In this case, the radar data from the radar system102 indicates when it is safe or unsafe to change lanes. Theautonomous-driving system may move the vehicle 104 to a particularlocation on the road while avoiding collisions with the object 108detected by the radar system 102. The radar data provided by the radarsystem 102 can provide information about a distance to and the locationof the object 108 to enable the autonomous-driving system to performemergency braking, perform a lane change, or adjust the speed of thevehicle 104.

The radar system 102 includes a transmitter 110 and at least one antenna114 to transmit electromagnetic signals, and a receiver 112 and the atleast one antenna 114 to receive reflected versions of theseelectromagnetic signals. The transmitter 110 includes components foremitting electromagnetic signals. The receiver 112 includes one or morecomponents to detect the reflected electromagnetic signals. Thetransmitter 110 and the receiver 112 can be incorporated together on thesame integrated circuit (e.g., a transceiver integrated circuit) orseparately on different integrated circuits.

The radar system 102 also includes one or more processors 116 (e.g., anenergy processing unit) and computer-readable storage media (CRM) 118.The processor 116 can be implemented as a microprocessor or asystem-on-chip. The processor 116 executes instructions that are storedwithin the CRM 118. As an example, the processor 116 can process EMenergy received by the antenna 114 and determine a location of theobject 108 relative to the radar system 102. The processor 116 can alsogenerate radar data for the automotive systems. As an example, theprocessor 116 can control, based on processed EM energy from the antenna114, an autonomous or semi-autonomous driving system of the vehicle 104.

FIG. 2 illustrates an example antenna 200 with a window 208 forisolation among antenna arrays. The antenna 200 includes a first antennaarray 202-1 and a second antenna array 202-2 on a PCB 206. The PCB 206includes a metal plating (e.g., copper alloy) on a top and/or bottomsurface.

The first antenna array 202-1 and the second antenna array 202-2 areconfigured to emit or receive electromagnetic energy. For example, thefirst antenna array 202-1 and the second antenna array 202-2 can be atransmit antenna array and a receive antenna array, respectively. Insome implementations, the first antenna array 202-1 and the secondantenna array 202-2 can be two transmit antenna arrays or two receiveantenna arrays. In other implementations, the antenna 200 can includeadditional antenna arrays 202 with at least one window 208 locatedbetween the antenna arrays 202.

The first antenna array 202-1 and the second antenna array 202-2 includemultiple antenna elements 204. The antenna arrays 202 can be planararrays that provide high gain and low loss. Planar arrays arewell-suited for vehicle integration due to their small size and depth.For example, the antenna elements 204 of the antenna arrays 202 can beslots etched or otherwise formed in the plating material of one surfaceof the PCB 206 for a substrate-integrated waveguide (SIW) antenna. Theantenna elements 204 can also include elements of an aperture antenna, amicrostrip antenna, or a dipole antenna. As an example, the antennaarrays 202 can include subarrays of patch elements (e.g., microstrippatch antenna subarrays) or dipole elements.

In the depicted implementation, the first antenna array 202-1 includesfive antenna elements, including an antenna element 204-11, an antennaelement 204-12, an antenna element 204-13, an antenna element 204-14,and an antenna element 204-15. The second antenna array 202-2 alsoincludes five antenna elements, including an antenna element 204-21, anantenna element 204-22, an antenna element 204-23, an antenna element204-24, and an antenna element 204-25. In other implementations, thefirst antenna array 202-1 and/or the second antenna array 202-2 caninclude fewer or additional antenna elements 204, including a singleantenna element 204.

In operation, the first antenna array 202-1 can transmit or receiveelectromagnetic energy 210-1. The metal plating on the surface of thePCB 206 can conduct a portion of the EM energy 212 from the firstantenna array 202-1 along the surface of the PCB 206. The second antennaarray 202-2 can receive the portion of the EM energy 212 conducted bythe metal plating. The second antenna array 202-2 couples the portion ofthe EM energy 212 with EM energy 210-2, which is emitted or received bythe second antenna array 202-2.

As an example, the first antenna array 202-1 can be a transmit antennaarray and the second antenna array 202-2 can be a receive antenna array.When the first antenna array 202-1 emits the EM energy 210-1, arelatively large portion of the EM energy 210-1 is radiatedperpendicular to the surface of the PCB 206 to illuminate potentialtargets within the field-of-view 106 of the radar system 102. The metalplating also conducts a portion of the EM energy 212 along the surfaceof the PCB 206. The second antenna array 202-2 can couple the portion ofthe EM energy 212 with the received EM energy 210-2. This coupling cancause a relatively high noise floor (e.g., coupling noise) in the EMenergy output by the second antenna array 202-2.

The at least one window 208 represents an exposed portion of the surfaceof the PCB 206 without the metal plating. It is also referred to assimply “the window 208” because the portion can be exposed in variousways, not only through etching. The window 208 is configured to act as aground point or ground window on the surface of the PCB 206. Forexample, the window 208 can represent a portion of the metal platingremoved or etched away from the surface of the PCB 206. As anotherexample, the window 208 can represent a portion of the surface of thePCB 206 masked during the metal-plating process for the PCB 206. In thisway, the surface of the PCB 206 includes an omitted region of metalplating, wherein the omitted region of metal plating represents thewindow 208.

The window 208 is positioned between the first antenna array 202-1 andthe second antenna array 202-2. The window 208 can generally bepositioned anywhere along the coupling path between the first antennaarray 202-1 and the second antenna array 202-2. A height of the window208 is generally less than a height of the first antenna array 202-1and/or a height of the second antenna array 202-2. As a result, a firstpart 212-1 of the portion of the EM energy 212 does not traverse thewindow 208, and a second part 212-2 of the portion of the EM energy 212does traverse the window 208.

A width of the window 208 is effective in delaying a phase of the secondpart 212-2 of the portion of the EM energy 212 relative to a phase ofthe first part 212-1 of the portion of the EM energy 212. The phase ofthe first part 212-1 of the portion of the EM energy 212 is delayed dueto effects from the dielectric constant of the PCB substrate (e.g.,slow-wave effect). The width of the window 208 can be sufficient tocause the phase of the second part 212-2 of the portion of the EM energy212 to be delayed by approximately 180 degrees relative to the phase ofthe first part 212-1 of the portion of the EM energy 212. The width ofthe window 208 can be determined from simulations, empirical analysis,or a combination thereof.

A height of the window 208 is effective to cause an amount of energy ofthe second part 212-2 of the portion of the EM energy 212 to beapproximately equal to an amount of energy of the first part 212-1 ofthe portion of the EM energy 212. In this way, when the portion of theEM energy 212 is coupled in the second antenna array 202-2, the widthand the height of the window 208 can be effective to minimize, or evenapproximately eliminate, the first part 212-1 against the second part212-2 of the portion of the EM energy 212. As a result, the couplingnoise at the second antenna array 202-2 can be minimized orapproximately eliminated.

FIG. 3 illustrates another example antenna 300 with a window 302 forisolation among antenna arrays. The antenna 300 is similar to theantenna 200 of FIG. 2, with many of the same or similar components. Theantenna 300 includes the first antenna array 202-1 and the secondantenna array 202-2 on the PCB 206.

Similar to the antenna 200 of FIG. 2, the first antenna array 202-1 ofthe antenna 300 can transmit or receive electromagnetic energy 210-1.The metal plating on the surface of the PCB 206 can conduct a portion ofthe EM energy 212 from the first antenna array 202-1 along the surfaceof the PCB 206. The second antenna array 202-2 can receive the portionof the EM energy 212 conducted by the metal plating. The second antennaarray 202-2 couples the portion of the EM energy 212 with EM energy210-2, which is emitted or received by the second antenna array 202-2.

Similar to the window 208 of FIG. 2, the window 302 of the antenna 300represents an exposed portion of the surface of the PCB 206 without themetal plating. The window 302 can include an irregular surface onopposite sides of the window 302 positioned adjacently to the firstantenna array 202-1 and the second antenna array 202-2. In someexamples, the irregular surface can include individual peaks and valleysarranged like teeth (e.g., a sawtooth). The irregular surface of thewindow 302 can minimize or avoid edge scattering of the second part212-2 of the portion of the EM energy 212 that traverses the window 302at the sides of the window 302. In other implementations, the sides ofthe window 302 can be curved down toward the PCB substrate to minimizeedge scattering.

FIG. 4 illustrates an example antenna 400 with multiple windows 208 forisolation among antenna arrays. The antenna 400 is similar to theantenna 200 of FIG. 2, with many of the same or similar components. Theantenna 400 includes the first antenna array 202-1 and the secondantenna array 202-2 on the PCB 206.

Similar to the antenna 200 of FIG. 2, the first antenna array 202-1 ofthe antenna 300 can transmit or receive electromagnetic energy 210-1.The metal plating on the surface of the PCB 206 can conduct a portion ofthe EM energy 212 from the first antenna array 202-1 along the surfaceof the PCB 206. The second antenna array 202-2 can receive the portionof the EM energy 212 conducted by the metal plating. The second antennaarray 202-2 couples the portion of the EM energy 212 with EM energy210-2, which is emitted or received by the second antenna array 202-2.

The antenna 400 includes a first window 208-1 and a second window 208-2.In other implementations, the antenna 400 can include additional windows208. Similar to the window 208 of FIG. 2, the first window 208-1 and thesecond window 208-2 of the antenna 400 represents an exposed portion ofthe surface of the PCB 206 without the metal plating.

The first window 208-1 and the second window 208-2 are positionedbetween the first antenna array 202-1 and the second antenna array202-2. The first window 208-1 and the second window 208-2 can bepositioned generally anywhere along the coupling path between firstantenna array 202-1 and the second antenna array 202-2.

A width of the first window 208-1 and the second window 208-2 iseffective to delay a phase of the second parts 212-2 and 212-4 of theportion of the EM energy 212 relative to a phase of the first parts212-1 and 212-3 of the portion of the EM energy 212. The width of thefirst window 208-1 is generally equal or approximately equal to thewidth of the second window 208-2.

A collective height of the first window 208-1 and the second window208-2 is effective to cause an amount of energy of the second parts212-2 and 212-4 of the portion of the EM energy 212 to be approximatelyequal to an amount of energy of the first parts 212-1 and 212-3 of theportion of the EM energy 212. In this way, when the portion of the EMenergy 212 is coupled in the second antenna array 202-2, the width andthe collective height of the first window 208-1 and the second window208-2 can be effective to minimize, or even cancel, the first parts212-1 and 212-3 against the second parts 212-2 and 212-4 of the portionof the EM energy 212.

In the depicted implementation, the first window 208-1 and the secondwindow 208-2 have a rectangular shape or an approximately rectangularshape. As a result, the first antenna array 202-1 is positionedadjacently to a first side of the first window 208-1 and the secondwindow 208-2 and the second antenna array 202-2 is positioned adjacentlyto a second side of the first window 208-1 and the second window 208-2opposed the first side. In other implementations, the window 208 of FIG.2, the window 302 of FIG. 3, the first window 208-1 of FIG. 4, and thesecond window 208-2 of FIG. 4 can have a different shape. A width andheight of the window(s) can be determined using simulations or empiricalanalysis to minimize or cancel the first part 212-1 of the portion ofthe EM energy 212 against the second part 212-2 of the portion of the EMenergy 212.

Example Method

FIG. 5 depicts an example method 500 of an exposed portion of a PCBconfigured to provide isolation among radar antennas. Method 500 isshown as sets of operations (or acts) performed, but not necessarilylimited to the order or combinations in which the operations are shownherein. Further, any of one or more of the operations may be repeated,combined, or reorganized to provide other methods. In portions of thefollowing discussion, reference may be made to the environment 100 ofFIG. 1, and entities detailed in FIGS. 1 through 4, reference to whichis made for example only. The techniques are not limited to performanceby one entity or multiple entities.

At 502, a first antenna and a second antenna are added to a surface of aPCB. For example, the first antenna array 202-1 and a second antennaarray 202-2 are added to a surface of the PCB 206.

At 504, a metal plating is applied to the surface of the PCB. The metalplating is configured to conduct a portion of the EM energy from thefirst antenna on the surface of the PCB. For example, a metal plating isapplied to the surface of the PCB 206. The metal plating conducts aportion of the EM energy 212 from the first antenna array 202-1 on thesurface of the PCB 206. The second antenna array 202 is configured toreceive the portion of the EM energy 212 and is coupled with the EMenergy 210-2.

At 506, an exposed portion of the surface of the PCB is provided. Theexposed portion is positioned between the first antenna and the secondantenna. For example, a window 208 is provided on the surface of the PCB206 and represents an exposed portion of the surface of the PCB 206. Thewindow 208 is positioned between the first antenna array 202-1 and thesecond antenna array 202-2.

At 508, a width of the exposed portion is set. The width is effective todelay a phase of a first part of the portion of the EM energy thattraverses the exposed portion relative to a phase of a second part ofthe portion of the EM energy that does not traverse the exposed portion.For example, the width of the window 208 is set. The width of the window208 is effective to delay a phase of the second part 212-2 of theportion of the EM energy that traverses the window 208 relative to thephase of the first part 212-1 of the portion of the EM energy that doesnot traverse the window 208.

At 510, a height of the exposed portion is set. The height is effectiveto cause an amount of energy of the first part of the portion of the EMenergy to be approximately equal to an amount of energy of the secondpart of the portion of the EM energy. For example, the height of thewindow 208 is set. The height of the window 208 is effective to causethe amount of energy of the first part 212-1 of the portion of the EMenergy to be approximately equal to the amount of energy of the secondpart 212-2 of the portion of the EM energy.

EXAMPLES

In the following section, examples are provided.

Example 1: A radar system comprising: a printed circuit board (PCB)comprising: a first antenna and a second antenna on a surface of thePCB, the first antenna and the second antenna configured to emit orreceive electromagnetic (EM) energy; a metal plating on the surface ofthe PCB, the metal plating configured to conduct a portion of the EMenergy from the first antenna on the surface of the PCB, the secondantenna configured to receive the portion of the EM energy conducted bythe metal plating; and an exposed portion of the surface of the PCB, theexposed portion positioned between the first antenna and the secondantenna and representing an area of the surface of the PCB without themetal plating, wherein: a width of the exposed portion is effective todelay a phase of a first part of the portion of the EM energy thattraverses the exposed portion relative to a phase of a second part ofthe portion of the EM energy that does not traverse the exposed portion;and a height of the exposed portion is effective to cause an amount ofenergy of the first part of the portion of the EM energy to beapproximately equal to an amount of energy of the second part of theportion of the EM energy.

Example 2: The radar system of example 1, wherein the width of theexposed portion is effective to delay the phase of the first part of theportion of the EM energy by approximately 180 degrees relative to thephase of the second part of the portion of the EM energy.

Example 3: The radar system of example 2, wherein the portion of the EMenergy represents a coupling noise at the second antenna, and the widthand the height of the exposed portion are further effective toapproximately eliminate the coupling noise.

Example 4: The radar system of example 1, wherein the exposed portionhas an approximately rectangular shape.

Example 5: The radar system of example 4, wherein the first antenna ispositioned adjacently to a first side of the approximately rectangularshape and the second antenna is positioned adjacently to a second sideof the approximately rectangular shape opposite the first side.

Example 6: The radar system of example 1, wherein a first side of theexposed portion adjacent the first antenna and a second side of theexposed portion opposite the first side include an irregular surface.

Example 7: The radar system of example 1, wherein the exposed portioncomprises multiple exposed portions positioned between the first antennaand the second antenna.

Example 8: The radar system of example 1, wherein the first antenna andthe second antenna comprise a first antenna array and a second antennaarray, respectively.

Example 9: The radar system of example 8, wherein the first antennaarray and the second antenna array comprise substrate-integratedwaveguide (SIW) antennas.

Example 10: The radar system of example 1, wherein the first antennacomprises a transmit antenna and the second antenna comprises a receiveantenna.

Example 11: The radar system of example 1, wherein the first antenna andthe second antenna comprise two transmit antennas or two receiveantennas.

Example 12: The radar system of example 1, wherein the first antenna andthe second antenna comprise at least one of an aperture antenna, amicrostrip antenna, and a dipole antenna.

Example 13: The radar system of example 10, the radar system furthercomprising an interface between the PCB and an automotive system of anautomobile, wherein the PCB is configured to output, via the interface,a signal based on the EM energy received by the second antenna.

Example 14: The radar system of example 1, wherein the area of thesurface of the PCB represents a portion of the metal plating etched fromthe surface of the PCB.

Example 15: The radar system of example 1, wherein the radar system isconfigured to be mounted to an automobile.

Example 16: The radar system of example 1, the radar system furthercomprising: an energy processing unit configured to process EM energy,including the portion of the EM energy, received by the second antenna,wherein the first part of the portion of the EM energy and the secondpart of the portion of the EM energy approximately cancel one another.

Example 17: The radar system of example 16, wherein the processor isfurther configured to control, based on the processed EM energy, anautonomous or semi-autonomous driving system of an automobile.

Example 18: A method of manufacturing a radar system comprising: addinga first antenna and a second antenna to a surface of a printed circuitboard (PCB), the first antenna and the second antenna configured to emitor receive electromagnetic (EM) energy; applying a metal plating on thesurface of the PCB, the metal plating configured to conduct a portion ofthe EM energy from the first antenna on the surface of the PCB, thesecond antenna configured to receive the portion of the EM energyconducted by the metal plating; and providing an exposed portion of thesurface of the PCB, the exposed portion positioned between the firstantenna and the second antenna and representing an area of the surfaceof the PCB without the metal plating, wherein: a width of the exposedportion is effective to delay a phase of a first part of the portion ofthe EM energy that traverses the exposed portion relative to a phase ofa second part of the portion of the EM energy that does not traverse theexposed portion; and a height of the exposed portion is effective tocause an amount of energy of the first part of the portion of the EMenergy to be approximately equal to an amount of energy of the secondpart of the portion of the EM energy.

Example 19: The method of example 18, wherein providing the exposedportion of the surface of the PCB comprises removing a portion of themetal plating on the surface of the PCB.

Example 20: The method of example 18, wherein applying the metal platingon the surface of the PCB comprises applying the metal plating to thesurface of the PCB with an omitted region of metal plating, the omittedregion of metal plating representing the exposed portion of the surfaceof the PCB.

CONCLUSION

While various embodiments of the disclosure are described in theforegoing description and shown in the drawings, it is to be understoodthat this disclosure is not limited thereto but may be variouslyembodied to practice within the scope of the following claims. From theforegoing description, it will be apparent that various changes may bemade without departing from the spirit and scope of the disclosure asdefined by the following claims.

What is claimed is:
 1. A radar system comprising: a printed circuitboard (PCB) comprising: a first antenna and a second antenna on asurface of the PCB, the first antenna and the second antenna configuredto emit or receive electromagnetic (EM) energy; a metal plating on thesurface of the PCB, the metal plating configured to conduct a portion ofthe EM energy from the first antenna on the surface of the PCB, thesecond antenna configured to receive the portion of the EM energyconducted by the metal plating; and an exposed portion of the surface ofthe PCB, the exposed portion positioned between the first antenna andthe second antenna and representing an area of the surface of the PCBwithout the metal plating, wherein: a width of the exposed portion iseffective to delay a phase of a first part of the portion of the EMenergy that traverses the exposed portion relative to a phase of asecond part of the portion of the EM energy that does not traverse theexposed portion; and a height of the exposed portion is effective tocause an amount of energy of the first part of the portion of the EMenergy to be approximately equal to an amount of energy of the secondpart of the portion of the EM energy.
 2. The radar system of claim 1,wherein the width of the exposed portion is effective to delay the phaseof the first part of the portion of the EM energy by approximately 180degrees relative to the phase of the second part of the portion of theEM energy.
 3. The radar system of claim 2, wherein the portion of the EMenergy represents a coupling noise at the second antenna, and the widthand the height of the exposed portion are further effective toapproximately eliminate the coupling noise.
 4. The radar system of claim1, wherein the exposed portion has an approximately rectangular shape.5. The radar system of claim 4, wherein the first antenna is positionedadjacently to a first side of the approximately rectangular shape andthe second antenna is positioned adjacently to a second side of theapproximately rectangular shape opposite the first side.
 6. The radarsystem of claim 1, wherein a first side of the exposed portion adjacentthe first antenna and a second side of the exposed portion opposite thefirst side include an irregular surface.
 7. The radar system of claim 1,wherein the exposed portion comprises multiple exposed portionspositioned between the first antenna and the second antenna.
 8. Theradar system of claim 1, wherein the first antenna and the secondantenna comprise a first antenna array and a second antenna array,respectively.
 9. The radar system of claim 8, wherein the first antennaarray and the second antenna array comprise substrate-integratedwaveguide (SIW) antennas.
 10. The radar system of claim 1, wherein thefirst antenna comprises a transmit antenna and the second antennacomprises a receive antenna.
 11. The radar system of claim 1, whereinthe first antenna and the second antenna comprise two transmit antennasor two receive antennas.
 12. The radar system of claim 1, wherein thefirst antenna and the second antenna comprise at least one of anaperture antenna, a microstrip antenna, and a dipole antenna.
 13. Theradar system of claim 10, the radar system further comprising aninterface between the PCB and an automotive system of an automobile,wherein the PCB is configured to output, via the interface, a signalbased on the EM energy received by the second antenna.
 14. The radarsystem of claim 1, wherein the area of the surface of the PCB representsa portion of the metal plating etched from the surface of the PCB. 15.The radar system of claim 1, wherein the radar system is configured tobe mounted to an automobile.
 16. The radar system of claim 1, the radarsystem further comprising: an energy processing unit configured toprocess EM energy, including the portion of the EM energy, received bythe second antenna, wherein the first part of the portion of the EMenergy and the second part of the portion of the EM energy approximatelycancel one another.
 17. The radar system of claim 16, wherein theprocessor is further configured to control, based on the processed EMenergy, an autonomous or semi-autonomous driving system of anautomobile.
 18. A method of manufacturing a radar system comprising:adding a first antenna and a second antenna to a surface of a printedcircuit board (PCB), the first antenna and the second antenna configuredto emit or receive electromagnetic (EM) energy; applying a metal platingon the surface of the PCB, the metal plating configured to conduct aportion of the EM energy from the first antenna on the surface of thePCB, the second antenna configured to receive the portion of the EMenergy conducted by the metal plating; and providing an exposed portionof the surface of the PCB, the exposed portion positioned between thefirst antenna and the second antenna and representing an area of thesurface of the PCB without the metal plating, wherein: a width of theexposed portion is effective to delay a phase of a first part of theportion of the EM energy that traverses the exposed portion relative toa phase of a second part of the portion of the EM energy that does nottraverse the exposed portion; and a height of the exposed portion iseffective to cause an amount of energy of the first part of the portionof the EM energy to be approximately equal to an amount of energy of thesecond part of the portion of the EM energy.
 19. The method of claim 18,wherein providing the exposed portion of the surface of the PCBcomprises removing a portion of the metal plating on the surface of thePCB.
 20. The method of claim 18, wherein applying the metal plating onthe surface of the PCB comprises applying the metal plating to thesurface of the PCB with an omitted region of metal plating, the omittedregion of metal plating representing the exposed portion of the surfaceof the PCB.